1. Field of the Invention
The present invention relates to a digital video signal processing system and a method, in which rotational transform of color coordinates is easily accomplished by a rotational transfer matrix prior to a color transfer matrix of a scaler without a hardware component therefor.
2. Description of the Related Art
For the development of digital technology and multimedia services, there has been developed various media supporting digital multimedia services. Moreover, when digital broadcasting services are widely commercialized, the production of a digital display apparatus would be greatly extended.
Contrary to a CRT (cathode ray tube) directly scanning a video signal, the digital display apparatus such as a PDP (plasma display panel), an LCD (liquid crystal display), etc., processing and displaying a digital video signal comprises a scaler converting a video signal into the output format fit to the display panel. The scaler converts an inputted video signal into a video signal to be displayed on a panel by adjusting a vertical frequency of the inputted video signal, a resolution (the number of pixels) and a ratio of a screen (16:9, 4:3).
FIG. 4 is a control block diagram of a conventional digital video signal processing system. As shown in FIG. 4, the conventional digital video signal processing system comprises a video decoder 103 processing a video signal for an NTSC (national television standards committee) TV or a VHS (video home system) video, an ADC (analog to digital converter) 101 processing a digital video signal for a DVD (digital versatile disk), an HD (high definition) TV, or etc., and a scaler 105 converting a video signal processed by the video decoder 103 or the ADC 101 into a video signal to be displayed on the panel.
The video decoder 103 receives a video signal for the NTSC TV, the VHS video, etc., and divides the video signal into a Y signal related to luminance and R-Y and B-Y signals related to chrominance. Herein, the R-Y and B-Y signals are employed in generating RGB (red, green, blue) signals. Hereinafter, the luminance (Y) signal and the chrominance (B-Y and R-Y) signals outputted from the video decoder 103 will be represented by a YCbCr signal.
The ADC 101 processes a video signal for the DVD, the HDTV, or etc., and the luminance (Y) signal and the chrominance (B-Y and R-Y) signals outputted from the ADC 101 will be represented by a YPbPr signal.
The scaler 105 includes a color transfer matrix 109 converting the YCbCr and YPbPr signals into digital RGB signals. The color transfer matrix 109 is previously determined according to the format of the video signal, and for example, FIG. 4 shows the color transfer matrix 109 converting the YCbCr signals into the digital RGB signals according to an ITU-RBT601 format. Therefore, the scaler 105 converts the YCbCr and YPbPr signals into the digital RGB signals by the color transfer matrix 109 while converting the YCbCr and YPbPr signals into video signals fit for the vertical frequency, the resolution, and the ratio of the screen according to the output format of the panel.
As described above, a conventional scaler converts an inputted video signal into a digital RGB signal by a predetermined matrix. However, in order to adjust hue in the conventional scaler, the scaler must have an IC (integrated circuit) capable of rotational transform of color coordinates of an inputted video signal, that is, to adjust the hue without the IC capable of the rotational transform of the color coordinates is not possible with a conventional scaler.